As a lens that magnifies an image of an observation object, a solid immersion lens (SIL: Solid Immersion Lens) is known. A solid immersion lens has a hemispherical shape or a hyperhemispherical shape called Weierstrass sphere, that is a microlens of about 1 mm to 5 mm in size. Then, provided that the solid immersion lens is installed so as to be made to contact closely with the surface of an observation object, its numerical aperture (NA) and magnification are both magnified, which enables an observation with high spatial resolution.
As an observation apparatus utilizing a solid immersion lens, for example, an apparatus disclosed in Patent Document 1 is known. The observation apparatus disclosed in Patent Document 1 includes a microscope having an objective lens, and a solid immersion lens holder which is coupled to a front end of the objective lens via an arm member, that holds a solid immersion lens on the front surface side of the objective lens.    Patent Document 1: International Publication No. 2005/043210 Pamphlet